Method for high resolution patterning using soft x-ray, process for preparing nano device using the same method

ABSTRACT

A method for nano-scale high resolution patterning of self-assembled monolayer using soft X-rays is provided. The method involves forming an aromatic imine molecular layer having substituents at its terminal rings on a substrate, selectively cleaving bonds to the subsituents of the aromatic imine molecular layer, and hydrolyzing the aromatic imine molecular layer.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a method for high resolutionpatterning and a process for manufacturing a nano device using the highresolution pattern, and more particularly, to a method for micro- ornano-scale high resolution patterning within a short period of time, anda nano device formed using the method.

[0003] 2. Description of the Related Art

[0004] With recent advances in the semiconductor industry and the needfor highly-integrated semiconductor devices, nano- or micro-fabricationtechnologies for minute patterning attract more and more attention.

[0005] As is expected by many experts that nanotechnology will be one ofthe leading technologies in the 21st century, nano-pattern fabricationis an essential technology of the highest priority in minute-circuitprocessing for large-capacity semiconductor devices. In addition,nano-patterning technology has wide applications, for example, in thebioengineering related field and for biosensors, so its consequencebecomes great.

[0006] So far, surface patterning has been achieved by photolithographyemploying deep UV radiation and polymer-photoresists, leading tostunning advances in the semiconductor industry for the last decade.

[0007] Pattern resolution in photolithography is determined according toRayleigh's equation, R=k₁λ/NA, where R denotes resolution, λ denoteswavelength, k₁ is a constant, and NA denotes the numerical aperture of alens system. A shorter wavelength of light used results in higherresolution and smaller patterns. A pattern resolution on the order of500 nm, achieved in the early 1980s by G-line (436 nm) exposure systemsusing high-pressure mercury lamps, has markedly been reduced to 180 nmrecently by the use of 248-nm KrF eximer laser exposure technology,thereby realizing the production of 1-Gb memory semiconductors (SolidState Technol., January 2000). However, due to the limitations in thewavelength of usable light, equipment and technology requirements, andthe resolution of polymeric photoresist used, it is difficult to formnano-scale high-resolution patterns with this method.

[0008] For higher pattern resolutions, many attempts have been madesince 1990, for example, using self-assembled monolayers as a newphotoresist, instead of polymers used in conventional photolithography,and using light of a short wavelength. In addition, new patterningtechnologies for self-assembled monolayers, for example, softlithography or scanning probe lithography using tips of AFM and STM havebeen introduced.

[0009] In the early 1990s, Whitesides, a professor at HarvardUniversity, termed surface patterning using an elastomeric stamp or moldto ink a solid substrate with the help of molecular self-assembly, notusing light or high energy particles, as “soft lithography” and reportedmany research results (Appl. Phys. Lett., 1993, 63, 2002). Arepresentative example is concerned with microcontact printing (μCP)involving stamping surfactant molecules, for example, alkanethiol, in asurface area with a polydimethylsiloxane (PDMS) elastomer stamp to formpatterns of self-assembled monolayers only on the stamping area. Thismicrocontact printing enables speedy and economical consecutivepatternings. However, this technique has some problems to be solved,such as inaccurate registration (<1 μm) due to the deformation of anelastomeric stamp, incompatibility with current integrated circuit (IC)processes, etc.

[0010] Recently, Mirkin et al. have developed “dip-pen” nanolithography(DPN) which uses an AFM tip as a “nib”, a solid substrate (for example,Au) as “paper”, and molecules with a chemical affinity for the solidsubstrate as “ink”. Molecules are delivered from the AFM tip to a solidsubstrate of interest via capillary transport (Science, 1999, 283, 661).Due to the use of elaborately formed sharp tips, dip-pen nanolithographyoffers a high-resolution, nano-scale pattern of about 5 nm. However, itstime-consuming serial pattern drawing processes limit commercializationthrough mass production.

SUMMARY OF THE INVENTION

[0011] Therefore, the present invention provides a method forfabricating a high resolution pattern of a desired shape within a shortperiod of time.

[0012] The present invention provides a substrate with a high resolutionpattern.

[0013] The present invention also provides a method for manufacturing ahigh-performance and miniaturized semiconductor device using the highresolution pattern.

[0014] The present invention also provides a method for manufacturing ahigh-density biochip using the high resolution pattern.

[0015] The present invention provides a method for high resolutionpatterning, comprising: (a) forming an aromatic imine monolayer havingsubstituted terminal rings on a substrate; (b) selectively removing thesubstituents from the aromatic imine monolayer; and (c) hydrolyzing thearomatic imine monolayer.

[0016] In an embodiment of the method according to the presentinvention, (a) forming the substituted aromatic imine monolayer on thesubstrate may comprise forming a aminosilylated or aminothiolatedself-assmebled monolayers on the substrate and processing the surface ofthe aminosilylated or amnothiolated monolayer with an aromatic aldehydehaving a substituted terminal ring.

[0017] The substituent of the aromatic aldehyde with the substitutedterminal ring may be a nitro group or halogen group.

[0018] The aromatic aldehyde having the substituted terminal ring may bea conjugated or non-conjugated aromatic aldehyde. The non-conjugatedaromatic aldehyde with the substituted terminal ring may be a compoundof formula (1) below:

[0019] where X is NO₂, F, Cl, Br, or I. The conjugated aromatic aldehydewith the substituted terminal ring may be a compound of formula (2),(3), or (4) below:

[0020] In formulae (2), (3), and (4) above, X is NO₂, F, Cl, Br, or I.

[0021] The substrate used in the present invention may be a silica orgold substrate.

[0022] In another embodiment of the high resolution patterning methodaccording to the present invention, (b) selectively removing thesubstitutents from the aromatic imine molecular layer may compriseexposing the substrate through a photomask to soft X-rays. In this case,the soft X-rays may have a wavelength of 0.3-10 nm at an energy of40-1,500 eV. The photomask may be a zone plate.

[0023] The present invention also provides a substrate with a nano-scalepattern featuring alternating height, chemical reactivity, andwettability on sub-100 nm dimensions, the substrate comprising a baseplate and a surface layer on the base plate, wherein the surface layerincludes a hydrophilic amine molecular layer in a region and ahydrophobic aromatic imine molecular layer in the other region whichform the nano-scale pattern together.

[0024] The present invention also provides a method for manufacturing asemiconductor device with a nano-scale pattern, the method comprisingcoating a diblock copolymer onto the above substrate having thenano-scale pattern and annealing and etching the substrate coated withthe diblock copolymer. The diblock copolymer may bepoly(stylene-block-methylmethacrylate). The present invention alsoprovides a biochip fabricated by immobilizing proteins, DNA, or RNA onamine groups previously attached to the above nanopatterned substrateaccording to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and other features and advantages of the presentinvention will become more apparent by describing in detail exemplaryembodiments thereof with reference to the attached drawings in which:

[0026]FIG. 1 illustrates a method according to the present invention forforming on a silica substrate an aromatic imine monolayer that is likelyto occur selective chemical transformation by soft X-ray irradiation;

[0027]FIG. 2 illustrates a method according to the present invention forforming on a gold substrate an aromatic imine monolayer that is likelyto occur selective chemical transformation by soft X-ray irradiation;

[0028]FIG. 3 illustrates a process for high resolution patterningaccording to the present invention into the aromatic imine monolayerusing a photomask;

[0029]FIG. 4 is a magnified atomic force microscopic photograph of apattern formed on the surface of a substrate in Example 1 according tothe present invention;

[0030]FIG. 5 is a magnified atomic force microscopic photograph of apattern formed on the surface of a substrate in Example 2 according tothe present invention;

[0031]FIG. 6 is an atomic force microscopic photograph of a patternformed in Example 4 according to the present invention by irradiationwith soft X-rays of 500 eV;

[0032]FIG. 7A is a magnified atomic force microscopic photograph at ascale of 22 μm×22 μm of a pattern formed in Example 4 by irradiationwith soft X-rays of 800 eV; and

[0033]FIG. 7B is a magnified atomic force microscopic photograph at ascale of 2 μm×2 μm of the pattern formed in Example 4 by irradiationwith soft X-rays of 800 eV.

DETAILED DESCRIPTION OF THE INVENTION

[0034] Hereinafter, the present invention will be described below indetail. According to the present invention, after forming an aromaticimine monolayer having substitutents at its terminal rings by reactingamine groups in an aminosilyated or aminothiolated monolayer previouslyformed on the substrate with an aromatic aldehyde compound havingvarious substitutents, the substituents are selectively cleaved from thearomatic imine molecular layer by soft X-rays irradiation (having awavelength of 0.1-10 nm at an energy of 40-1,500 eV), which isaccompanied by chemical changes in the molecular layer, therebyresulting in a high-resolution pattern.

[0035] The aromatic aldehyde compound that provides the substituents tobe selectively cleaved may be a nitro-substituted or halogenatom-substituted benzaldehyde having formula (1) below or conjugatedaromatic aldehyde.

[0036] where X is NO₂, F, Cl, Br, or I.

[0037] Suitable conjugated aromatic aldehydes include any aldehydecompound having one terminal substituted with a nitro group or halogenatom and the other terminal capable of forming an imine bond bycondensation with the amine group on the surface of the substrate.However, the compounds having formulae (2), (3), and (4) below capableof binding to amine groups on the substrate surface at a high densityand inducing a great pattern height difference are preferred.

[0038] In formulae (2), (3), and (4) above, X is NO₂, F, Cl, Br, or I.

[0039] As described above, the amine groups in the aminosilyated oraminothiolated monolayer on the surface of a silica substrate or goldsubstrate are reacted with the aromatic aldehyde compound by heating inethanolic solution under an inert gas atmosphere, so that the aromaticimine molecular layer is formed on the substrate.

[0040] When the aromatic imine monolayer is heated in pure deionizedwater, imine bonds are hydrolyzed to separate the aromatic aldehyde fromthe amino silane molecular or amino thiol molecular layer on thesubstrate. As a result, the hydrophilic amine groups are exposed on thesurface of the substrate.

[0041] However, once the aromatic imine molecular layer is irradiatedwith soft X-rays, the substituents on the terminal ring of the aromaticimine monolayer, which may be nitro groups or halogen group atoms, areselectively cleaved, and the imine bonds on the surface of the molecularlayer are transformed into non-hydrolyzable chemical species, therebyresulting in a new molecular layer. At this time, a surface region ofthe substrate from which the substituents have been cleaved showshydrophobic property.

[0042] As described above, when soft X-ray irradiation onto thesubstituted aromatic imine monolayer through an appropriately designedphotomask is followed by hydrolysis in deionized water, an irradiatedregion of the molecular layer that is not hydrolyzed becomes to have ahydrophobic surface having the aromatic ring, whereas a non-irradiatedregion of the molecular layer where the imine groups are hydrolyzedbecomes to have a hydrophilic surface having the amine group. As aresult, a desired high-resolution pattern of alternate hydrophilic andhydrophobic regions can be formed on the surface of the substrate.

[0043] Hereinafter, a method for forming a nano-scale high resolutionpattern on a substrate according to the present invention will bedescribed with reference to the appended drawings.

[0044] Initially, a method for forming an aromatic imine monolayer usingaminosilylated substrates will be described. A substrate on which thearomatic imine molecular layer will be formed is washed and dried. Theclean substrate was immersed into a solution (20 mL) containing a silanecoupling agents under nitrogen atmosphere, and placed in the solutionfor 6 h. Any amino silane compound producing no acidic byproduct, forexample, (3-aminopropyl)diethoxymethylsilane, may be used withoutlimitations. An example of solvent for dissolving the amino silanecompound may be toluene. Any kind of substrate, for example, a silicasubstrate, a gold substrate, etc., may be used in the present inventionwithout limitations. When a gold substrate is used, it is preferable totreat the gold substrate with an alkane thiol compound having an aminegroup at its terminal.

[0045] When the above amino silylation is completed, the substrate iswashed with a solvent and dried.

[0046] The amino-silylated substrate is immersed and heated in anethanolic solution of a nitro- or halogen-substituted aromatic aldehydecompound under an inert gas atmosphere. The heating temperature mayrange from 20° C. to 100° C., and the heating time may range from 1 hourto 20 hours. After the reaction is completed, the substrate is washedwith an organic solvent.

[0047] Through the above-described processes a substrate with thearomatic imine molecular layer, as shown in FIG. 1, can be obtained.

[0048] Another embodiment of a substrate with an aromatic iminemolecular layer according to the present invention is illustrated inFIG. 2. The substrate of FIG. 2 is prepared in a similar manner as inthe previous embodiment described with reference to FIG. 1, except thata gold substrate and an amino thiol compound are used instead of thesilica substrate and the amino silane compound, respectively. An exampleof the amino thiol compound used in the present embodiment to form amonomolecular layer may be 3-aminopropanethiol. Ethanol may be used as asolvent for dissolving the amino thiol compound.

[0049] A substrate with an aromatic imine molecular layer as shown inFIGS. 1 and 2 is dried in a vacuum and fixed to a metallic sampleholder. A photomask having a desired feature size and shape is placed onthe substrate with a separation gap of about 1-10 μm. If the separationgap between the photomask and the substrate is greater than 10 μm, it isdifficult to form a pattern having a feature size of 200 nm or less dueto light diffraction effects. If the separation gap between thephotomask and the substrate is less than 1 μm, the surface of thesubstrate may be unnecessarily contaminated, and the photomask is highlylikely to be broken.

[0050] The substrate with the aromatic imine molecular layer fixed tothe sample holder and covered with the photomask is placed into anultra-high vacuum chamber. When the ultra high vacuum chamber isevacuated to 10⁻⁸ torr or less, soft X-rays are perpendicularly radiatedonto the surface of the substrate. The soft X-rays may have a range ofwavelengths from 0.3 nm (equivalent to 1500 eV) to 10 nm (equivalent to40 eV). The duration of soft X-ray irradiation is determined to be longenough for the nitro group or halogen atom on the outermost molecularsurface of the substrate to be cleaved and separated out. The durationof soft X-ray irradiation may be varied according to the structure ofthe aromatic imine molecular layer bound to the surface of the substrateand the kind of substituents of the molecular layer. If the wavelengthof the soft X-rays is shorter than 0.3 nm, the molecular layer isindiscriminately destroyed. If the wavelength of the soft X-rays islonger than 10 nm, undesirably the substituents cannot be selectivelycleaved from the aromatic imine molecular layer.

[0051] After the substrate with the aromatic imine molecular layerexposed to the soft X-rays is drawn out of the ultra-high vacuumchamber, the substrate is immersed in pure deionized water andhydrolyzed at a temperature of 20-80° C. for, preferably, about 1-10hours. The substrate after the hydrolysis is washed with an organicsolvent and dried in a vacuum.

[0052] Through the above-described processes, a pattern of an organicmolecular layer can be formed on the substrate, as shown in FIG. 3.

[0053] Referring to FIG. 3, in a soft X-ray irradiated region of theorganic molecular layer, the nitro group or halogen atom is selectivelycleaved, which is accompanied by chemical transformation of the iminebond to be resistant to hydrolysis, thereby resulting in a hydrophobicsurface having the aromatic ring. In a non-irradiated region of theorganic molecular layer, the imine bond is hydrolyzed so thathydrophilic amine groups are generated on the surface of the substrate.As a result, the irradiated and non-irradiated regions of the organicmolecular layer pattern have a height difference equal to the dimensionof the aromatic ring and can be visualized using atomic force microscopy(AFM).

[0054] A substrate with a nano-scale pattern according to the presentinvention can be used as a base substrate in manufacturinghighly-integrated semiconductor circuits. In particular, when thenano-scale pattern of alternate hydrophobic and hydrophilic regions onthe substrate is coated with a diblock copolymer, the height to whichthe diblock copolymer piles up differs by hundreds of nanometers betweenthe separate hydrophobic and hydrophilic regions. When the substrate isimmersed in an appropriate etchant, the high and low regions on thesubstrate are etched to different degrees, thereby transferring thenano-scale pattern into the substrate.

[0055] In particular, a diblock copolymer, for example,poly(styrene-block-polymethylmethacrylate), is coated onto the substratewith the nano-scale pattern formed according to the present invention ina planar structure using, for example, spin coating. On the hydrophilicregion of the substrate, polymethylmethacrylate (PMMA) is firstarranged, and polystyrene (PS), PS, PMMA, PMMA and PS are sequentiallypiled thereon, with the upper and outermost layer of PS having a lowsurface free energy, leading to an asymmetric wetting of the surface.Meanwhile, on the hydrophobic region of the substrate, PS is firstarranged, and PMMA, PMMA, and PS are sequentially piled thereon, leadingto a symmetric wetting of the surface.

[0056] When the substrate with the diblock copolymer thin film isthermally treated at a high temperature, a molecular rearrangementoccurs, and the symmetric wetting and asymmetric wetting regions becometo have a quantized thickness of nL₀ and (n+1/2)L₀, respectively,wherein L₀ represents the thickness of a repeating unit, i.e., PS-PMMA,in the planar layer structure. In a region where the initial thicknessis thinner than a quantized thickness after the thermal treatment, ahole is generated, s. while, in a region where the initial thickness isthicker than a quantized thickness after the thermal treatment, anisland is formed. In result, the height contrast of the pattern isamplified.

[0057] When the substrate that has been thermally treated is subject toetching, a portion of the organic molecular layer on the surface of thesubstrate is removed to provide a semiconductor device with a nano-scalepattern. Types of etching which can be used include any common etchingapplied in the manufacture of semiconductor devices, for example, usinga mixture of KCN and KOH solutions or a HF solution as an etchant.

[0058] A semiconductor device manufactured with a nano-patterning systemaccording to the present invention as described above can overcome afeature size limit of 130 nm (or 90 nm), which is known to be thehighest resolution that can be achieved using currently practicalsemiconductor manufacturing processes.

[0059] Since a nano-scale high resolution pattern according to thepresent invention has a hydrophilic portion with amine groups that canreadily bind to enzymes or other functional substances, it can beapplied to biosensors and various material-related fields. Inparticular, since the hydrophilicity and hydrophobicity of the patterncan be easily controlled on a nano-scale, the advantage of the patternis the greatest when used for high density protein chips.

[0060] In a nano-scale high resolution pattern formed by the methodaccording to the present invention, a region of highly reactive andhydrophilic amine groups serves as a reaction site to whichbiomolecules, such as proteins, DNA, or RNA can selectively bind. Also,a hydrophobic region of the high resolution pattern, which is alternatedwith the hydrophilic region, serves as a barrier for different kinds ofbiomolecules to diffuse without being mixed. Therefore, a nano-scalehigh resolution pattern formed according to the present invention can beapplied to a surface of a substrate in order to form an array of variouskinds of biomolecules on the surface through biomolecular interactions.Therefore, the nano-scale high resolution pattern according to thepresent invention is considered to greatly contribute to the productionof high-integrated, high-throughput, miniature biochips.

[0061] In general, biochips are manufactured by immobilizingbiomolecules on a substrate directly or via linker molecules. Forexample, a protein chip with antibody molecules can be manufactured byimmobilizing the antibody molecules on a solid substrate throughchemical interactions with amine groups previously attached to thesurface of the solid substrate.

[0062] The present invention will be described more fully with referenceto the accompanying drawings, in which examples of the invention areshown. This invention may, however, be embodied in many different formsand should not be construed as being limited to the examples set fourthherein; rather these examples are provided so that this disclosure willbe thorough and complete, and will fully convey the concept of theinvention to those skilled in the art.

EXAMPLE 1

[0063] Initially, a cleaned silica substrate was dried in a vacuum ofabout 20 mtorr. A round-bottom flask was charged with a solution of(3-aminopropyl)diethoxymethylsilane in toluene (10⁻³M) under a nitrogenatmosphere. The dried silica substrate was immersed in that solution andreacted at room temperature for silylation.

[0064] After the silylation was completed, the substrate was washed withtoluene, dried in an oven at 120° C. for 30 minutes, and cooled to roomtemperature. The cooled substrate was washed by ultrasonication intoluene, a solvent mixture of toluene and methanol in 1:1 by volume, andthen methanol for 3 minutes each, and dried in a vacuum.

[0065] Next, the amino-silylated silica substrate was immersed in asolution of 20 mg of 4-nitrobenzaldehyde in 25 mL of ethanol for 6 hoursin a nitrogen atmosphere for condensation. At this time, the reactiontemperature was maintained at 50° C.

[0066] The substrate after the reaction was washed with excess methanoland by ultrasonication in methanol and then ethanol for 1 minute each,and dried in a vacuum.

[0067] The resulting 4-nitrobenzealdimine molecular layer on the silicasubstrate was cut to a size of 1 cm×1 cm, fixed to an aluminum sampleholder, covered with a photomask with a separation gap of 5 μm betweenthe molecular layer and the photomask, and placed into a ultra-highvacuum chamber. When the ultra-high vacuum chamber was evacuated to 10⁻⁸torr or less, soft X-rays of 500 eV were perpendicularly radiated ontothe substrate for 6.5 hours. The photomask used was a transmissionelectron microscopic (TEM) grid of a 1000-mesh size (G-1000HS, EnergyBeam Sciences Inc.) The soft X-ray irradiation was performed on a 4B1photoemission electron microscopy (PEEM) beam line of Pohang AcceleratorLaboratory in Korea.

[0068] After being drawn out of the ultra-high vacuum chamber, thesubstrate was immersed in a mixture of 3 mL of pure deionized water and1 mL of ethanol at 50° C. for 6 hours for hydrolysis. The substrateafter the hydrolysis was washed by ultrasonication in a mixture ofdeionized water and ethanol and then acetone for 3 minutes each, anddried in a vacuum.

[0069] The resulting pattern on the substrate was confined using atomicforce microscopy. The result is shown in FIG. 4.

EXAMPLE 2

[0070] A substrate with a pattern was manufactured in the same manner asin Example 1, except that a gold substrate instead of the silicasubstrate and 3-aminopropanethiol instead of the (3-aminopropyl)diethoxymethylsilane were used for amino-thiolation. A cleaned goldsubstrate was immersed in a solution of 3-aminopropanethiol in ethanol(10 mM) and reacted for 3 hours in a nitrogen atmosphere for theamino-thiolation. The substrate after the amino-thiolation was washedwith an organic solvent and dried in a vacuum.

EXAMPLE 3

[0071] An aromatic imine molecular layer was formed on the substrate inthe same manner as in Example 1, except that 4-nitrocinnamaldehydeinstead of the 4-nitrobenzaldehyde was used. In patterning, soft X-raysof 500 eV were radiated onto the substrate for 4.5 hours until 80% ofthe nitro group was removed from the terminal ring in the aromatic iminemolecular layer. Hydrolysis was carried out according to Example 1.

EXAMPLE 4

[0072] A substrate with a pattern was manufactured in the same manner asin Example 1, except that a zone plate, consisting of engraved goldconcentric circles with varying linewidth from hundreds of nanometers totens of nanometers on silicon nitride membrane, was used as a photomask.In the present example, a zone plate with a minimum feature size of 80nm in the outer-zone was used as the photomask. When such a zone plateis used as a photomask, the transmittance of soft X-rays through thesilicon nitride membrane reduces to about 50%. For this reason, the softX-rays were radiated for about 24 hours, which is double the duration ofX-ray irradiation in Example 1. The soft X-rays were radiated at both500 eV and 800 eV energy levels.

EXAMPLE 5

[0073] A substrate with a pattern was manufactured in the same manner asin Example 1, except that 4-nitrocinnamaldehyde instead of the4-nitrobenzaldehyde was used, and a zone plate instead of the TEM gridwas used as the photomask. The soft X-rays were radiated at both 500 eVand 800 eV energy levels. For the reason described in Example 4, theduration of soft X-ray irradiation was extended to about 10 hours foreach energy level.

EXAMPLE 6

[0074] A 2% diluted solution by weight of a symmetricpoly(stylene-block-methylmethacrylate) copolymer (available from PolymerSource Inc.) in toluene was coated onto the silica substrate with thenano-pattern manufactured in Example 1 using spin coating at 2,500-3,000rpm. The resulting polymer thin film was thermally treated in a vacuumoven at 180° C. for 24 hours. The substrate after the thermal treatmentwas immersed in an alkaline solution of 0.01 M KCN and 2M KOH containingCN⁻ ions and stirred continuously to manufacture a semiconductor devicewith a nano-scale pattern.

EXAMPLE 7

[0075] The silica substrate with the nano-pattern manufactured inExample 1 was reacted with succinimidyl 4-maleimido butyrate (SMB) toimmobilize linker molecules thereon. For the immobilization, SMB wasinitially dissolved in a DMF solvent and diluted ten fold with sodiumhydrogen carbonate buffer (50 mM, pH 8.5) to a concentration of 20 mM.3′-SH-15mer-Cy3-5′ was dissolved in a spotting solution (10 mM HEPES, 5mM EDTA, pH 6.6), followed by an addition of DMSO (40% by volume). Thespotting solution mixture was spotted on the substrate on which thelinker molecules had been immobilized, using a pin-type spottinginstrument for microarrays and left at room temperature and a humidityof 70-75% for 3 hours to manufacture a biochip.

Experimental Example 1

[0076] Thickness and Surface Density Measurements

[0077] Before reaction with the aromatic aldehyde compound in the aboveexamples, the thickness of the aminosilyated or the aminothiolatedmonolayers and the density of amine groups on the surface of themolecular layer were measured. As a result, the thickness of themolecular layer ranged from 8 Å to 10 Å, and the surface density ofamine groups was about 3.5 amines/nm². After the condensation of theaminosilylated monolayer with 4-nitrobenzaldehyde and4-nitrocinnamaldehyde, the thickness increased by 4-6 Å and 6-8 Å,respectively.

Experimental Example 2

[0078] Atomic Fore Microscopic Analysis

[0079] The substrate with the pattern manufactured in Example 1 wasanalyzed using atomic force microscopy (AFM), as shown in FIG. 4. Thephotograph of FIG. 4 at a scale of 10 μm×10 μm shows a region of thesubstrate where TEM grid patterns of a 5-μm width intersect. In FIG. 4,outer regions of the intersection appear bright. The bright regions arebelieved to be higher than the level of the intersection by about 4 Å.In particular, the bright regions were irradiated with light through theTEM grid used as the photomask, so that the nitro group was selectivelycleaved and chemical transformation of the imine group occurred in thoseregions to be resistant to hydrolysis, thereby resulting in ahydrophobic surface having aromatic rings. As a result, the height ofthe irradiated regions was greater than that of the non-irradiatedregion where the 5-μm grid patterns intersect to shield light, by adegree equal to the dimension of the aromatic ring.

[0080] The gold substrate with the pattern manufactured in Example 2 wasalso analyzed using AFM. As a result, a similar pattern to that shown inFIG. 4 was observed on the surface of the gold substrate.

[0081]FIG. 5 is an AFM photograph of the pattern formed on the substratein Example 3. Apparently, the soft X-ray irradiated region andnon-irradiated regions (corresponding to the intersection of 5-μm gridpatterns) have a height difference equal to the dimension of thearomatic ring. Since 4-nitrocinnamaldehyde having an alkene bond(—CH₂═CH₂—), which is not present in the 4-nitrobenzealdehyde used inExample 1, was used in Example 3, the pattern formed in Example 3 showeda height difference of about 6 Å, which is greater than in Example 1.

[0082]FIGS. 6 and 7 are AFM photographs of patterns formed on substratesin Example 4. FIG. 6 shows an edge region of 5 μm×5 μm in the patternformed by irradiation with soft X-rays of 500 eV through the zone plate.The pattern has a feature size of about 150-300 nm and becomes narrowerfrom right toward left. A line with a feature size of 80 nm was observedat a region further to the left. Bright and dark regions of the patternshown in FIG. 6 had a height difference of about 7 Å.

[0083]FIGS. 7A and 7B are AFM photographs of a pattern formed on asubstrate by irradiation with soft X-rays of 800 eV through the zoneplate. FIG. 7A shows an inner-zone of the zone-plate imaged surfaces ata scale of 22 μm×22 μm. A partial concentric pattern with a smallerfeature size toward a lower part of the photograph is apparent. FIG. 7Bshows an outer-zone of the pattern magnified to 2 μm×2 μm. A leftportion of the photograph shown in FIG. 2B is a non-pattern region thatis unblocked by the zone plate, and a right portion is an outermostpattern region having pattern lines. As expected, a 80-nm pattern linewas apparently patterned into the substrate.

[0084] The results of the AFM analysis confirms that surface patterningon a scale of a few nanometers can be achieved using the nano-scalepatterning method according to the present invention with a higherresolution mask.

[0085] According to the present invention, a desired nano-scale highresolution pattern having alternate hydrophilic and hydrophobic regionscan be formed on a surface of a substrate within a short period of time.The substrate with such a nano-scale high resolution pattern is greatlyuseful as a base substrate that is accompanied by coating with acopolymer and selective surface etching in the semiconductor materialfield. Due to the reactive hydrophilic amine groups in the pattern,binding with enzymes or various functional substances can be controlledon a nano-scale. Therefore, nano-scale high resolution patterningaccording to the present invention can greatly contribute to thedevelopment of highly-integrated biochips or miniaturized biosensors.

[0086] While the present invention has been particularly shown anddescribed with reference to exemplary embodiments thereof, it will beunderstood by those of ordinary skill in the art that various changes inform and details may be made therein without departing from the spiritand scope of the present invention as defined by the following claims.

What is claimed is:
 1. A method for high resolution patterning,comprising: (a) forming a self-assembled aminosilylated oraminothiolated monolayers on a substrate and processing the surface ofthe self-assembled aminosilylated or aminothiolated monolayers with anaromatic aldehyde having a substituted terminal ring, to thereby form anaromatic imine monolayer having the substituted terminal ring on thesubstrate; (b) selectively removing the substituents from the aromaticimine monolayer; and (c) hydrolyzing the aromatic imine monolayer. 2.The method of claim 1, wherein the aromatic aldehyde having thesubstituted terminal ring is a conjugated aromatic aldehyde or anon-conjugated aromatic aldehyde.
 3. The method of claim 2, wherein thenon-conjugated aromatic aldehyde with the substituted terminal ring is acompound of formula (1) below:

where X is NO₂, F, Cl, Br, or I.
 4. The method of claim 2, wherein theconjugated aromatic aldehyde with the substituted terminal ring is acompound of formula (2), (3), or (4) below:

where X is NO₂, F, Cl, Br, or I.
 5. The method of claim 1, wherein thesubstituent of the aromatic aldehyde is a nitro group or a halogengroup.
 6. The method of claim 1, wherein the substrate is formed ofsilica or gold.
 7. The method of claim 1, wherein (b) selectivelyremoving the substitutents from the aromatic imine monolayer comprisesexposing the substrate to soft X-rays through a photomask placed on thesubstrate.
 8. The method of claim 7, wherein the soft X-rays have arange of wavelengths from 0.3 nm to 10 nm at an energy of from 40 eV to1,500 eV.
 9. The method of claim 7, wherein the photomask is a zonemask.
 10. A substrate with a nano-scale pattern of a predeterminedshape, the substrate comprising: a base plate; and a surface layer onthe base plate, the surface layer including a hydrophilic aminemonolayer in a region and a hydrophobic aromatic imine monolayer in theother region which form the nano-scale pattern together.
 11. A methodfor manufacturing a semiconductor device, the method comprising: coatinga diblock copolymer onto the substrate of claim 10; and thermallyprocessing (annealing) and etching the substrate coated with the diblockcopolymer.
 12. The method of claim 11, wherein the diblock copolymer ispoly(stylene-block-methyl methacrylate).
 13. A biochip comprising: thesubstrate of claim 10; and biomolecules bound to amine groups of thehydrophilic amine molecular layer.
 14. The biochip of claim 13, whereinthe biomolecules are proteins, DNA, or RNA.